Generally speaking, graphic media are very useful for presenting information to their viewers. For example, graphic data representations on printed and other media are in common use. Information represented graphically may be accessed by scanning their media to retrieve data stored therewith.
Scanners typically illuminate graphic data media while exposing a photosensor to capture light reflected therefrom. The captured light corresponds to an image taken of the graphic data representation. The taken image is processed to read the graphic data representation.
Data are represented in some graphic media using two dimensional (2D) geometric pattern arrays, such as bar code patterns (“barcodes”). Barcodes are used for presenting graphic data over a wide variety of commercial, consumer, logistic and industrial applications and in other fields.
Barcodes may be printed on a variety of media. For example, barcodes may be printed on labels for paper documents, products, parcels, tickets, coupons, stamps, scrip, etc. While useful in many applications, such printed media may sometimes at least border on legacy in others.
In other fields related to, e.g., identity, financial and security uses, barcodes may be encoded, transmitted, and rendered electronically with display screens associated with computers. Increasingly, such computers comprise portable or mobile computing and communicating devices (“mobile devices”).
Scanner devices must thus be operable for accessing graphic data presented in the printed media, as well as for retrieving data presented on mobile device display components. The tasks involved in these respective operations differ. Moreover, these operating differences are by no means trivial.
Scanning printed media typically proceeds with illumination of the media by a light source of the scanner. However, display screens of mobile devices are typically self-lit and have reflective viewing surfaces. Light from scanner sources thus “washes out” (obscures) data presented therewith.
Some scanners suppress their illumination supply to prevent such wash outs and improve data retrieval from mobile device display screens. However, such scanners may lose access to data on printed media. Duplicating scanners to read different media would be clearly impracticable and costly.
Issues related to this dichotomy are typically approached with trade-offs in performance characteristics, such as achievable suitable image quality from each of various media. For example, printed media scan quality improvements may reduce image quality from scans of electronic displays.
Typically, scanners light sources illuminate scan targets for the same length of time that their shutters are open for capturing light reflected therefrom. As illumination and exposure durations are equal, light reflected from mobile device displays increases along with exposure.
To ameliorate such reflection, some scanners reduce their light source brightness to scan display screens by decreasing power fed thereto. While the power reduction boosts significance of self-lighting from the scan target displays, motion tolerance qualities of the scan are reduced.
Other conventional scanners are operable to expose a first image with the scanner illumination source activated. The exposed first image is processed to try to determine if a self-lit display is present. If so, the scanner discards the first image and disables its light source temporarily.
Upon disabling its light source, the scanner then exposes a second image, in which the illumination is provided solely with the self-lighting of the image target display. Such scans clearly consume time and processing devoted to the first image for identifying the scan target as a display.
More time and processing resources are then consumed in disabling the scanner light source, and reimaging the display scan target. Unfortunately, identifying the scan targets as displays is sometimes inaccurate, thus compounding inefficiencies that may already be apparent for some scanners.
Therefore, a need exists for capturing graphic information presented on self-lit displays as well as in printed media. A need also exists for capturing graphic information, whether presented on self-lit displays or in printed media, without requiring multiple image captures.
Further, sufficient motion tolerance is needed in scanning graphic information presented either on self-lit displays or in printed media. Moreover, graphic information presented either on self-lit displays or in printed media needs to be captured efficiently, quickly and economically.
Issues or approaches within this background section may, but not necessarily have, been conceived or pursued previously. Unless otherwise indicated to the contrary, it is not to be assumed that anything in this section corresponds to any alleged prior art merely by inclusion in this section.